PDTC通过抑制NF-κB及下游通路减轻大鼠急性RIHD

PDTC attenuates radiation-induced heart damage by inhibiting the activation of NF-KB and its downstream signaling pathways in rats

目的探讨吡咯烷二硫代氨基甲酸盐（PDTC）能否通过抑制NF-κB及下游通路减轻大鼠急性RIHD。 方法将21只成年雄性SD大鼠随机分为空白对照组、单纯照射组和PDTC＋照射组3组各7只。单纯照射组及PDTC＋照射组大鼠接受心前区局部6 MV X线20 Gy单次照射。PDTC＋照射组在照射前30 min腹腔注射PDTC，120 mg/kg，1次/d，第1—14天。照射后第14天取心脏组织观察病理学变化，通过Masson染色计算心肌CVF，蛋白印迹法及实时荧光定量qPCR分别检测3组大鼠心肌组织的NF-κB家族成员p50、p65、HIF-1α、CTGF、COL-1蛋白及mRNA表达量变化。采用t检验差异。 结果HE染色结果显示PDTC＋照射组与单纯照射组比较，大鼠心肌细胞水肿减轻，炎症细胞浸润得到改善，成纤维细胞减少。Masson染色结果显示PDTC干预可减轻照射后大鼠心肌细胞间质胶原沉积，半定量分析结果显示PDTC＋照射组大鼠的CVF为（9.99±0.32）%，与单纯照射组的（22.05±0.21）%下降（P〈0.05）。蛋白印迹和qPCR结果显示PDTC＋照射组大鼠心肌组织p50、p65、HIF-1α蛋白表达及mRNA水平较单纯照射组均明显下降（P均〈0.05）；CTGF蛋白表达水平及mRNA水平较单纯照射组有下降趋势（P均〉0.05）；COL-1蛋白表水平达较单纯照射组下降（P〈0.05）；mRNA水平较单纯照射组有下降趋势（P〉0.05）。结论PDTC可通过抑制NF-κB的激活及其下游HIF-1α的转录减轻大鼠急性RIHD。

ObjectiveTo investigate whether pyrrolidine dithiocarbamate （PDTC） can attenuate the acute radiation-induced heart damage （RIHD） by inhibiting the activation of NF-κB and its downstream signaling pathways in rat models.MethodsTwenty-one male adult Sprague-Dawley （SD） rats were randomly divided into the blank control, irradiation and PDTC plus irradiation groups （n=7 for each group）. In the irradiation and PDTC＋ irradiation groups, the rats received 6 MV X-ray at a single fraction of 20.0 Gy. In the PDTC＋ irradiation group, intraperitonal injection of PDTC was administered at a dose of 120 mg/kg body weight, 30 minutes prior to radiation, once daily for 1-14 days. On the 14th day, pathological changes of myocardial tissue were observed. Masson’s trichrome staining was performed to calculate the collagen volume fraction （CVF） of myocardial cells. The expression levels of NF-κB family members including p50, p65, HIF-1α, connective tissue growth factor （CTGF） and collagen type 1（COL-1） proteins and mRNA were quantitatively measured by Western blot and quantitative real-time PCR （qPCR）. Statistical analysis was conducted by using t-test. ResultsHE staining demonstrated that compared with the irradiation group, the severity of myocardial edema was alleviated, the infiltration of inflammatory cells was mitigated and the quantity of fibroblasts was reduced in the PDTC＋ irradiation group. Masson’s trichrome staining revealed that PDCT intervention could decrease the deposition of collagen fiber in the interstitial tissues. Semi-quantitative analysis demonstrated that the CVF value in the PDTC＋ irradiation group was （9.99±0.32）%, significantly lower compared with （22.05±0.21）% in the irradiation group （P〈0.05）. Western blot and qRT-PCR demonstrated that the expression levels of p50, p65, and HIF-1αproteins and mRNA in the PDTC＋ irradiation group were significantly down-regulated compared with those in the irradiation group （all P〈0.05）. Compared with the irradiation group, the expression levels of CTGF protein and mRNA tended to decline （all P〉0.05）, and the expression levels of COL-1 protein and mRNA were equally inclined to decrease （P〈0.05 and P〉0.05）. Conclusion PDTC can alleviate the acute RIHD by suppressing the activation of NF-κB and its downstream HIF-1α transcription.